NGC 1637

Source: Wikipedia, the free encyclopedia.
J2000 epoch)
ConstellationEridanus
Right ascension04h 41m 28.229s[1]
Declination−02° 51′ 28.94″[1]
Redshift0.00239[2]
Heliocentric radial velocity717.1±1.2 km/s[2]
Distance9.77 ± 1.82 Mpc (31.9 ± 5.9 Mly)[3]
9.18 Mpc (29.9 Mly) h−1
0.73[4]
Apparent magnitude (V)11.5[5]
Apparent magnitude (B)11.25[6]
Characteristics
TypeSAB(rs)c[3] or SBc(s)II.3[7]
Apparent size (V)4.0′ × 3.2′[5]
Other designations
AGC 440323, LEDA 15821,[8] PGC 15821[5]

NGC 1637 is an isolated, non-interacting[7] intermediate spiral galaxy in the constellation Eridanus, about a degree to the WNW of the star Mu Eridani.[9] It is located at a distance of about 9.77 ± 1.82 Mpc (31.9 ± 5.9 Mly) from the Milky Way.[3] The galaxy is inclined at an angle of 31.1° to the line of sight from the Earth and the long axis is oriented along a position angle of 16.3°.[3]

In 1991, Gérard de Vaucouleurs and associates assigned a morphological classification of SAB(rs)c to NGC 1637, indicating a spiral galaxy with a weak bar structure (SAB) across the nucleus, surrounded by a partial ring (rs) and somewhat loosely-wound arms (c).[7] While the inner section of the galaxy shows a symmetrical two-arm structure,[6] it has a single outer spiral arm that wraps 180° around the nucleus,[6] giving the galaxy an overall asymmetric, lopsided appearance.[7] The outer spiral arm has a red component that indicates a significant age.[6] However, the existence of this structure is difficult to explain.[7] The galaxy shows indications of recent starburst activity that may have terminated around 15 million years ago.[6]

The active central nucleus shows weak LINER behavior, and it may be an intermediate form between a LINER and an H II region.[7] The luminosity of the X-ray source at the nucleus is 1.2×1038 ergs s−1 in the 0.3–7 keV band.[6]

A type II-P

″ to the southwest of the galaxy center. It received the designation SN 1999em and was the brightest supernova discovered that year, reaching magnitude 13.1.[10] The location corresponds to a deprojected galactocentric separation of 1.3 kpc (4.2 kly).[3]

Video showing the location of NGC 1637

References

  1. ^
    S2CID 18913331
    .
  2. ^
    S2CID 123380349
    .
  3. ^
    doi:10.1093/mnras/sts145
    .
  4. ^ "NASA/IPAC Extragalactic Database". Results for NGC 1512, Co-Moving Radial Distance. Retrieved 2014-12-18.
  5. ^ a b c "NASA/IPAC Extragalactic Database". Results for NGC 1637. Retrieved 2006-11-25.
  6. ^
    doi:10.1086/377474
    .
  7. ^
    doi:10.1086/300163
    .
  8. ^ "NGC 1637". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-08-14.
  9. ISBN 0-933346-84-0
    .
  10. ^ "Bright Supernovae - 1999". Astronomy Section, Rochdale Academy of Science. Retrieved 2020-08-14.

External links

  • Media related to NGC 1637 at Wikimedia Commons
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